The invention concerns a machine for harvesting root crop, in particular in the form of a complete potato harvesting machine; comprising a lifting device that in a position of use on a harvest field lifts several rows of the crop with admixtures from the soil transversely to the travel direction in accordance with a lifting width, wherein from the lifting device the loosened mixture of crop and admixtures by means of a first longitudinal conveyor is movable opposite to the travel direction and is transferred onto a second screening belt conveyor, wherein between longitudinal conveyor and screening belt conveyor a transfer zone is defined that comprises a belt overlap:
Machines for harvesting and processing root crop, in particular potatoes, have been known for a long time in various embodiments of pull-behind devices or self-propelled machines. In such machine configurations, lifting devices that lift several rows of crop with admixtures from the soil are used in connection with a downstream conveying and cleaning system. DE 32 35 087C2 discloses such a construction in connection with a root crop harvesting machine that is pulled by a tractor.
In a potato harvesting machine according to DE 93 20 575.9 U1, a screen conveyor with which the crop and the admixtures are supplied to the next cleaning stage is provided downstream of a lifting device that is provided with lifting shares.
A more complex configuration of a pulled potato harvesting machine according to DE 10 2007 034 446 A1 comprises, also downstream of a lifting device, a first longitudinal conveying device which is effective in combination with a second screening belt stage secured in the same frame construction. In this context, downstream of a transfer zone provided with a belt overlap, an upward conveying action of the mixture is provided. In this context, all of the conveying and cleaning component groups are secured on a substantially closed frame construction of the machine so that a linear movement to an upper deflection and sorting section is realized.
A similar construction is provided for a self-propelled complete potato harvesting machine (brochure “SF 150/170-60” of the company Grimme Landmaschinenfabrik GmbH & Co. KG, Damme, Germany, publication number: L05.0851.DE04/08/2000; 2008) wherein a first cleaning unit that receives the crop and is provided with a receiving belt and a first screen belt and a second cleaning unit with a second screen belt are arranged in linear sequence behind each other as conveying component groups. A similar system has already been disclosed in DE 36 31 969 A1 wherein respective transverse conveyor belts are associated herein with the second belt. DE 296 13 018 U1 discloses a potato harvesting machine in which the ridge lifting device and the downstream screening belts are arranged separate from each other on the lifting rocker and the main machine frame.
In the technical further development of such harvesting machines for root crop, for improving the cleaning and sorting conditions, respective components of the conveying complex that are arranged downstream of the leading receiving and cleaning system or respective belt component groups that are provided for manual sorting, for example, in the area of transfer conveyor belts, are replaced by larger component groups that, in relation to the machine frame, may cause a lateral projection. This affects at the same time handling of the system that is to be steered along the field contour because performing a complete lifting process, in particular near the respective edge zones of the field, may be affected by projecting components of the machine and crop loss can thus occur. In the aforementioned concept of the self-propelled complete potato harvesting machines according to the aforementioned brochure “SF 150/170-60”, the steering and drive unit is arranged upstream of the pickup system for the crop so that the corresponding length of the machine is considerable.
The object of the invention is to provide a machine for harvesting root crop, in particular in the form of a complete potato harvesting machine, which, with a minimal technical expenditure, can be used as a compact unit so that also in a tight moving space along a boundary area of the harvest field an optimal lifting process is possible and therefore crop losses can be avoided and travel movements at the edges of the field are improved.